ALMOST before Stephen Spender became a poet he was involved in what we like to believe is the real world. As a teen-ager he had a $20 printing press and turned out bottle labels for druggists.

(He also printed a little book of poems by a fellow Oxford student named W.H. Auden. There were about 20 copies, he thinks. One sold recently for $10,000. "Unfortunately, I don't have a copy myself," he says.)

Spender is 74 now, and still passionately involved in life and justice on the Third Planet. This week he was in town on a visit from London to get people interested in a magazine called Index on Censorship, which is becoming a sort of Amnesty International for words.

"It started when I saw a letter in The Times from Pavel Litvinov, and he told about the dissidents in Russia and how they manage to write and distribute their work, and he asked for any sympathizers to communicate," Spender told a select group at the home of Atlantic publisher Mortimer Zuckerman the other night. Litvinov is the grandson of the late Maxim Litvinov, one of the last major Soviet diplomatic figures with strong ties to the West.

Realizing that "well, perhaps one should do something about it," Spender started rallying friends all over the world and fired back a telegram signed by, among others, Auden, Henry Moore, Mary McCarthy, Bertrand Russell, Igor Stravinsky and Julian Huxley. It was 1968, and it took six months for a reply to arrive from Russia. Eventually the bi-monthly magazine was founded, to tell the world about suppression, harassment and imprisonment of writers in Russia, Eastern Europe, Latin America, South Africa, the Greece of the Colonels' regime and anywhere else it appeared, and also to print the suppressed works.

"As a writer, I would want not to be forgotten," he said. "I would want someone to say where and how I am, and also that my works should be published."

He called for the international community of writers, artists and intellectuals to help, "because it is really helping ourselves."

So far the magazine, partly funded by a Ford grant, has been operating on a modest scale with contributions from private foundations, publishers and the British Arts Council. The Norwegian government gave about $4,500. British playwright Tom Stoppard, who was born in Czechoslovakia, produced about $24,000 with a benefit.

For Stephen Spender, all this is nothing new. In 1937, in his brief days as a Communist, he entered Spain on a pass forged by his friend Andre' Malraux, to observe the civil war and attend an international writers' congress. It was the era of nonintervention, and Britons weren't allowed into the country, but people at the Spanish border couldn't have cared less.

"We thought the future of Europe hung on that war, and if the republicans won, that would prevent a world war. It's an old paradox: People fighting always think they're fighting for peace," he said. After World War II he worked for UNESCO; later he was co-editor of Encounter magazine, a post he quit upon learning that it was supported by CIA money. He was poetry consultant for the Library of Congress in 1965-66.

"British and American poets are traditionally involved in public life. That whole generation in America, Lowell, Berryman, Roethke, Jarrell, deeply felt they ought to be influencing American life and politics. They were terribly distressed by Vietnam and suffered deeply from the lack of recognition: They felt they were restricted to academia, to the campuses, and that the whole nation ought to be listening to them. It comes from Emerson and Whitman. . ."

Artists have always been visionaries, it seems. In England, deep in the 19th century, Carlyle and Ruskin and others sensed that the entire structure of Victorian Europe was about to break down. They wrote about it, as did some of the more prescient politicians. Still, Spender says, these days the public in Anglo-Saxon countries doesn't take poetry as seriously as people do in Russia and Spain and some other places.

"It's the students who respond to poetry. Perhaps they think that's what students do."

He knows a lot about students. A lecturer at universities from Cincinnati to Berkeley, not to mention Cambridge, he has written a book of essays, "The Year of the Young Rebels," about the extraordinary international outburst of student anger in 1968.

"It was a kind of replay of 1870," he observed, "especially in France, where they built barricades on the streets and all. It was so much the same scenario that the authorities took it seriously. De Gaulle was terrified and took a helicopter through France and Germany trying to get hold of his army, and then he wanted to resign, and he had to be dissuaded from all this."

At Columbia University, where Spender first encountered the unrest of '68, "the professionals got frightfully depressed, and enlightened ones like Lionel Trilling thought everything they stood for had been wrecked, but then, a generation of students only lasts three years, and perhaps they had struck a particularly ungrateful generation of them."

In Germany, he said, the rebellion was extremely cruel, with women students stripping in class and dancing around their teachers, mocking them. In Prague, they wanted consumer goods, cars to take them out of the cities and into the country away from the urban hassle. In England, "it was all very academic," and students would gleefully talk of protest parades whose purpose no one quite understood.

Today, students and others in Europe are marching again. "It's the bomb. Students seem to be hypnotized by it. I always wish they'd associate it with the causes of war itself, but they don't, really. The whole protest against the Americans is very strong throughout the world, and this is partly stupid but partly because you can't protest against Russia: It just doesn't have any effect. If they thought the Russians were open to be demonstrated against, they'd do it."

He sees tensions rising everywhere, with censorship tightening in Eastern Europe ("even in England there's this anti-pornography thing now") amid the general disappointment that Brezhnev's death failed to produce any rescission.

He has seen such times come, and pass, and come again, this tall man with the thick white hair, the ruddy skin, the still brilliantly blue eyes, this poet with the quietly romantic name who once wrote:

Why cannot the one good

Benevolent feasible

Final dove, descend?

And the wheat be divided?

And the soldiers sent home?

And the barriers torn down?

And the enemies forgiven?

And there be no retribution?

Because the conqueror

Is victim of his own power . . .

It is two dozen prose works and 55 years worth of poetry since Spender's bright early days as a leader of the Oxford Group, when his lyrical voice was compared to Shelley's and the world seemed ready to be changed. He is still writing. Two years ago he and David Hockney, the British artist, visited China and wrote a book about it. He is still lecturing, still reading his poems to audiences who call out for this favorite or that beloved classic ("I think continually of those who were truly great . . ."), still battling for the right of people everywhere to speak out and be heard.

That poem above, "The War God," ends like this:

The world is the world

And not the slain

Nor the slayer, forgive.

There's no heaven above

To make passionate histories

End with endless love.

Yet under wild seas

Of chafing despairs

Love's need does not cease.